Pelagic trawls include trawls used to catch Alaska pollock, blue whiting, capelin, herring, mackerel, pearlside, hoki, hake and other fish species. Pelagic trawls have their pelagic mesh formed mainly of ropes. Pelagic mesh in a pelagic trawl is mesh having a mesh size that is three meters (3 m) and greater. A main problem in the pelagic trawl fishing industry and the pelagic trawl net manufacturing industry is high operational costs minimizing profitability. Price competition is severe and thus high cost and high quality ropes such as ropes used in climbing applications, yachting applications and seismic applications, to name a few are not feasible for use in forming the pelagic mesh of pelagic trawls because the pelagic mesh are constantly damaged and replaced, and require replacement even when not damaged as they are made as thin and as light as possible in order to minimize drag and concurrent fuel consumption, and thus are worked at high loads relative to break points and therefore fail rather quickly. For this reason, more costly coverbraided (including “overbraided”) ropes, as opposed to braid jacketed twines used in small mesh netting of say lesser than six hundred millimeters (600 mm) mesh size, are not favored for forming the pelagic mesh of pelagic trawls. Indeed, considering the world wide pelagic trawl industry as a whole, it is a fact that it is against the trend in the industry to design and form the pelagic mesh portion of pelagic trawls from coverbraided ropes.
Due to the severe price competition, presently the vast majority of pelagic trawls have their pelagic mesh portion formed of non-jacketed braided or twisted twines. These are low cost to produce, low cost to replace, and easy to splice. It is important that the ropes be easy to splice as splicing has become the dominant form of connecting front part mesh in pelagic trawls as it is much stronger than knotting and also much lower in drag than knotting, allowing much lowered manufacture costs as well as lowered drag and concurrent lowered fuel consumption. The difficulty in splicing coverbraided ropes and especially in splicing tightly coverbraided ropes such as helix ropes is another reason that coverbraided ropes have lost favor among pelagic trawl manufacturers and end users.
One of the main problems caused by the fact that coverbraided ropes are largely out of favor in forming the pelagic mesh portion of pelagic trawls is that the most easily handled and in fact the preferred variant of self spreading meshed trawls employ a coverbraid in the self spreading rope construction and it is self spreading trawls that have the lowest environmental impact of all pelagic trawl constructions. Thus, it is important to increase market demand for self spreading trawls in order to increase the use of low environmental impact pelagic trawls. Ultimately, it is catch per unit effort that is most important to fishing company customers. Therefore, if such new self spreading rope constructions are to gain acceptance by the fishermen, newer and better self-spreading rope constructions for self spreading trawls must better some factor that the bettering of which improves the catch per unit effort. Likewise, if market demand is to be increased for such self-spreading trawls, that are the variety of pelagic trawls that have the lowest environmental impact of any type of pelagic trawl, such self spreading trawls must increase the catch per unit effort.
The main factor in improving catch per unit effort of pelagic trawls at the rope level is to reduce the drag of a rope at angles of attack found in the pelagic netting portions of pelagic trawls and consequently the drag of a pelagic trawl. Even more importantly, is to both reduce the drag while concurrently either maintaining the amount of lift and/or increasing the amount of lift compared to what is presently exhibited by the lowest drag embodiments of self spreading trawls. The reduced drag concurrently reduces fuel consumption, and also can increase trawl opening, while sufficient lift maintains the trawl open along its length during turns and side currents thereby permitting marine mammal escape and precluding marine mammal by-catch. In addition to preventing marine mammal by-catch, the self spreading trawls being able to retain open their long dimension during turns and side currents means that fish herded into and along the length of the trawl are not sieved through the mesh and de-scaled and lost, to die of de-scaling while not being counted to the catch quota, but rather are properly herded into the collection bag and counted to the catch quota. The counting to the catch quota of fish killed by the trawl is essential to preserving healthy fisheries as well as to preserving the food source for marine mammals and seabirds. Furthermore, both the lower drag of as well as the sufficient lifting forces of self spreading trawls independently or concurrently lead to increased catch per unit effort, and thus lead to increased customer acceptance and demand, causing the self spreading trawls to be used with their favorable environmental properties as opposed to use of alternative trawl types that do not possess the favorable environmental impact properties of self spreading trawls.
Helix ropes, as defined above and also further defined herein, are used in self spreading pelagic trawls known as “Helix Trawls” manufactured and sold by Hampidjan HF of Iceland. The original teaching of such helix ropes is contained within now Published Patent Cooperation Treaty (PCT) International Publication No. WO/1998/046070, International Application No. PCT/US1998/007848 (see FIG. 29), and a latter teaching of such helix ropes also is contained within now Published Patent Cooperation Treaty (PCT) International Publication No. WO 03/081989 A2, International Application No. PCT/US03/10114 (see FIG. 6). Helix ropes, and the “Helix Trawls” manufactured by Hampidjan HF of Iceland, have acquired a reputation of exhibiting excessively greater drag than modern, state of the art cordage used to form other pelagic trawl nets and especially non-self spreading pelagic trawl nets in the present state of the art. The increased drag concurrently results in smaller trawl openings, reduced towing speed and increased fuel consumption at given tow speeds. For this reason the use of helix ropes to form self spreading trawls such as Helix Trawls has not gained wide acceptance among fishing entities, despite the fact that they offer other favorable properties, such as preventing by-catch of marine mammals that would otherwise be caught in non-self spreading trawls when the back end of such non-self spreading trawls collapses, such also as enhanced ability to selectively fish as the trawls do not collapse, and other. Problematically, it is the helix ropes that also are the preferred form of a self spreading rope for forming a self spreading pelagic trawl because they are the most reliable embodiment of a self spreading rope useful for forming a self spreading pelagic trawl, other embodiments having lost favor and no longer being in use.
Beyond the highly favorable environmental factors of helix rope formed pelagic trawls, there are other instances when helix rope formed pelagic trawls are highly useful. These include in slow trawl speed applications, and in quick turning applications at deep depths with much warp out, as in these circumstances the self spreading properties of self spreading trawls prevents the trawls from collapsing, thereby not only preventing by-catch of marine mammals and enhancing selective fishing, but also maintaining the trawl fishing the selected species for a greater portion of the time. So, where such operational conditions prevail it is favorable to the final catch per unit effort equation to employ even the presently known higher drag and higher cost self spreading trawls formed of the helix rope. However, these circumstances are not the norm, but rather are the exception, and in such cases the greater fuel consumption of such trawls is not favored, but rather tolerated and it remains that lowering drag and concurrently lowering fuel consumption is a most important factor in increasing customer demand for such environmentally favorable trawls.
In attempt to solve problems present with known Helix ropes, International Application No. PCT/EP2010/060663 having International Publication No. WO 2011/009924 A2, and International Application No. PCT/EP2010/060670 having International Publication No. WO 2011/009929 A2 teach further embodiments for Helix ropes where such embodiment are lowered drag embodiments. However, as taught in such references, such embodiments also are higher in cost to produce than prior embodiments of Helix ropes. For this reason, these embodiments have failed to be adopted. Thus, it can readily be appreciated that it is important not only to reduce the drag of helix ropes, but also to reduce the cost of manufacturing a lowered drag helix rope. Furthermore, as the cost of a helix rope is widely considered in relation to an amount of strength obtained from a helix rope for a certain cost to produce such helix rope, it can readily be appreciated that it is important to both lower the drag of a helix rope as well as to reduce the cost to manufacture a lowered drag helix rope in order to accelerate adoption into the commercial midwater and/or pelagic trawl fishing industry of the environmentally friendly helix rope and thus permit the fisheries, fish and resource as well as the fishermen, marine mammals and seabirds whose livelihoods depend upon such fish and resource to benefit from the reduced by-catch and reduced fossil fuel consumption associated with the use of a lowered drag helix rope in forming midwater and/or pelagic trawls.
Thus, it can readily be appreciated that a long felt needs exists to provide an alternative rope that reduces drag in comparison to known helix rope constructions while also maintaining the positive characteristics and associated benefits of known helix rope constructions, so as to reduce the drag of pelagic trawls, while maintaining positive benefits, in order to once again generate favor among fishing entities to use the low environmental impact self spreading trawls that also greatly enhances marine mammal safety and permits more selective fishing, while concurrently reducing fuel consumption per unit of fish caught.
Thus also, it can readily be appreciated that a long felt needs exists to provide a rope having reduced drag as well as reduced manufacture costs, compared to known helix rope constructions, so as to reduce the drag and cost of pelagic trawls formed of such helix rope.
Thus yet again also, it can readily be appreciated that a long felt needs exists to provide a rope having reduced drag compared to known helix ropes, to reduce the manufacture costs of trawls formed of such reduced drag ropes, and also to at least preserve the amount of lift that such reduced drag and reduced cost ropes are capable of generating while subject to a water stream and yet more preferably to increase the amount of lift such ropes are capable of creating while subject to a water stream, so as to reduce the drag and cost of pelagic trawls formed of such ropes while concurrently enhancing the environmentally superior properties of such trawls.
To further describe a helix rope: a helix rope is a type of a “coverbraided” rope, the term “coverbraided” rope also known herein and in the industry as “overbraided” rope. The cover or sheath is formed by a braided sheath that is itself formed of strands. What distinguishes a helix rope from any other type of tightly coverbraided rope useful in forming pelagic mesh in pelagic trawls is that in a helix rope one of the strands forming the braided sheath is substantially larger than the other strands forming the braided sheath. The state of the art and the trend in the industry in forming any helix rope for the commercial pelagic trawl net industry is to form the braided sheath, including the spiraling strand, where the spiraling strand either is:
(a) one of a total quantity of strands forming the braided sheath where: (i) the total quantity of strands forming the braided sheath preferably is an even number quantity; and (ii) the spiraling strand follows the same path around and about the outside of the strength member core as do all other strands forming the braided sheath; and
(b) the spiraling strand follows the same path around and about the outside of the strength member core as do all other strands forming the braided sheath (i.e. has the same pick angle and/or same braid angle and/or same lay angle and/or same amount of advance as do other strands forming the braided sheath), with some alternative embodiments of such embodiment including that the spiraling strand is not included within the braided sheath but is adhered and/or otherwise formed onto the outside surface of the braided sheath, such as by extrusion.
Thus, it can readily again be appreciated that the present state of the art as well as the present trend in the industry teaches one to form a helix rope where the path that a spiraling strand follows along and about the outside of the strength member core and/or around and about the external portion of the helix rope is same as the path followed by individual strands forming the remainder of the braided sheath that is formed about the outside of the strength member core.
One advantage of known constructions of helix ropes is that all strands forming the braided sheath are similarly tightly bound to the strength member core as well as to one another, making for a very tightly braided enveloping braided sheath that tightly binds the enclosed strength member core, thereby making for a maximally rigid coverbraided rope, as is the goal of the industry in employing coverbraids about strength member cores. That is, it is the goal of the industry to achieve a maximally rigid rope for use in pelagic trawl mesh when forming a coverbraid about a strength member core, and for this reason the coverbraid is formed as tight as feasible, as the tighter the coverbraid, the more rigid the resulting rope. It thus can readily be appreciated that the state of the art and the trend in the industry is to make all strands forming a braided sheath about a strength member core equally tightly bound to the strength member core and unable to have any part of any of the strands forming the cover braid be pulled away from the core by the fingers of a person of usual strength when the rope is bent or when it is not bent. This is accomplished by both maxing the tension on the braiding strands as tight as feasible during the coverbraided process while also forming the coverbraid in such a fashion and construction that all strands forming the coverbraid have a same pitch, and are all equally woven into the braided construction of the coverbraided sheath enveloping the strength member core.
Thus, it can readily again be appreciated that the present state of the art as well as the present trend in the industry teaches one to form a helix rope where a spiraling strand included in the helix rope has a same pitch as do other strands forming the braided sheath of the helix rope.